1. Field of the Invention
The present invention relates to an electrical connector and, more particularly, to an electrical connector for use in flat multiple layer cable systems wherein the end portion of a multiple layer cable extends into a connector housing and comprises various stepped layers each of which includes a row of contact points. Similarly, the end portion of a multiple layer printed wiring board extends into the connector housing and comprises various stepped layers each of which includes a row of contacts or terminals. The stepped layers of the cable mate with the stepped layers of the board and are spring loaded by spring means which are provided inside of the connector housing for urging the connector contact points into electrical and physical engagement with the board terminals with which the contact points mate. Such an electrical connector is referred to herein as a multiple layered connector, and such a printed wiring board is referred to herein as a multiple layered printed wiring board. The connector assembly of this invention comprises the multiple layered printed wiring board inserted into the multiple layered connector.
2. Description of Prior Art
Prior art electrical connectors have been produced utilizing electrical contacts which are manufactured from a solid metallic strip or wire which has been subjected to several manufacturing operations. Not only are such operations costly but use of the contacts so produced involves various limitations in the connectors which comprise such contacts. For example, the usual configuration of such contacts places undesirable limitations upon the degree of contact density within the connector housing. This is true even regarding those connectors wherein contact density can be increased to some extent by a further reduction in contact spacing or contact size. In addition, in many applications the contacts must not only carry current but also must be produced from a resilient material so that the contacts can resile towards and engage printed wiring board terminals when in operation. Accordingly, in selecting a material for use as an electrical contact a compromise must be made in order to satisfy the requirements that the contact be resilient and conductive to the extent desired.
Prior art attempts have been made to increase contact density by utilizing multiple layered flat cable in electrical systems. However, heretofore multiple layered cable has not been particularly conducive for use with standard electrical connectors of the type wherein a multiple layered printed wiring board may be readily inserted into or removed from a receptacle formed by a connector body. For example, some attempts to utilize multiple layered flat cable in such applications where a plurality of closely spaced electrical contacts are required within a relatively small connector housing have involved complex interconnection between connector contacts and the various circuit layers of the cable. In such applications, plated holes are made in the cable at ninety degrees to the appropriate circuit layer. Subsequently, the tails or end portions of the connector contacts are inserted through such holes, and electrical continuity between the contacts and circuity is effected by means of solder or interface fits. Such complex interconnections undesirably limit contact density. In addition, the plated holes are expensive to produce.
It is therefore one of the objects of the present invention to provide a multiple layered connector for use in flat cable systems and into which may be readily inserted, or from which may be readily removed, a multiple layered printed wiring board.
Another object of the present invention is to provide a multiple layered connector wherein a plurality of closely spaced electrical contacts may be provided within a small connector housing.
A further object of the present invention is to provide a multiple layered connector having contacts manufactured from a conductive material selected independent of the material used to manufacture the spring means used to urge the contacts into electrical and physical engagement with the terminals of a printed wiring board inserted into the connector.
Yet a further object of the present invention is to provide a multiple layered connector having spring means, for urging connector contacts into electrical and physical engagement with the printed wiring board terminals, manufactured from a resilient material selected independent of the material used to manufacture the connector contacts.
Yet another object of the present invention is to provide a multiple layered connector which is simple in construction.
A further object of the present invention is to provide a multiple layered connector having electrical contacts which may be manufactured without requiring several of the operations heretofore considered necessary.
These and other objects will become apparent from the detailed discussion which follows and from the accompanying drawings.